Process for making aromatic nitro compounds



Patented Dec. 29, 1931 HARRY K. IHRIQ'OF man'rrnnzfioanironnm,nssrenon or ONE-HALF 'ro sUMnEn E.

CAMPBELL, or' ASSOCIATED, CALIFORNIA No Drawing."

My invention relates to the preparation of aromatic derivatives from hydrocarbon ma terials. r i 1' I p Briefly stated it consists inthe concentra- 5 tion of the aromatic,ihydro-ar0matic and unsaturated compounds in an extract formed the treatment of a hydrocarbon material with :0 consisting of unsaturated, hydro-aromatic and aromatic hydrocarbons concentrated in I a relatively smallvolume; treating said extract with a suitable reagent for the removal of the unsaturated hydrocarbons' thereby leaving a remainder comprising a mixture of aromatic, hydro-aromatic andpartially hydrogenated aromatic compounds; nitrating said remainder or any distillate fraction thereof; and separating from. said nitrated 3o remainderor fraction a mono-nitro compound.-' My invention more in detail will now be fullydisclosed. 1 1 First, asto the preparation of the extract. A number of crude oils are'shown to containhydrocarbons other'than the saturated straight chain hydrocarbons Such other hy drocarbons may be classified asQun'saturated aliphatic, hydroraromati'c and aromatic hydrocarbons. Sometimes hydro-aromatic hydrocarbons are known 'napt henes,

hydrocarbons thanthe saturated type ofhy as differentiated. from thesaturated aliphatic,

or non-polar hydrocarbons; The full hydrocarbons, therelis vdiflioulty usingthe 01 rnoonss non -M.AKING ARo A'rIo n'rrao oomrounns;

Application filed January 31,11927. Serial no. 165,046.

," ATE T oFFICE drogenated aromatic compounds are midway between the non-polar and polar types 7 In order to, separate polar hydrocarbons from non-polar hydrocarbons, it is necessary to employ some means other than distillation. One of these means is the extractionvwith a polar solvent, the polarhydrocarbons going into solution in the polar solvent, and the non-polar hydrocarbons remaining behind as a separate layen', Examples of such .polar solvents are liquid sulphur dioxide, liquid am monia, or liquid hydrochloric acid. These solvents are gases at ordinary temperatures and pressures and hence can'be readily removed after the extractionhasbeenmade and then can be used for'further repetitions of thecycler v 1 i Vi The polar solvent most used-in petroleum refining is liquid sulphur dioxide because of its cheapness and-relative ease of liquefaction; In using liquid sulphur dioxide the hydrocarbon material-is agitated with liquid sulphur dioxide -at=15 F. and l pound gage pressure. Thismay be done either in batches, or continuously by having the liquidsulphur dioxide flow counter-currently totheh drocarbon material. After the liquid su 'phur dioxide has become thoroughly mixed in in timate contact with the hydrocarbon material the mixture is allowed to settle. Two layers are observed; atop layer, which. con sists of the non-polar type of hydrocarbons relatively free of sulphur dioxide, and the lower layer compos'edof a' solution of, the polar hydrocarbons and some other impurities, in liquidsulphur dioxide. The lowerlayer is drawnoff and the sulphur dioxide evaporated for further use inthe cycle. "The upper layer is called' 'raflinat and consists of the non-polar hydrocarbons, and is used either as such or given appropriate additional In the refining i Oils co t g Su other re ning treatment to make high quality re fined oil products. The lower layer is known as'extract and at present is used for fuel,"-or for making anti-detonating motor fuel.

. w The extract is the material referred to herein and is the starting point of my process. It

consists of unsaturated, hydro-aromatic, and

aromatic hydrocarbons concentrated in a relatively' small-1 volume and with "relatively small amounts of inert non-polar hydrocarbons. This material is therefore valuable as the starting point for the production of derivatives of the above mentioned hydrocarbons concentrated in it. In preparing the extract the hydrocarbon material is chosen of appropriate boiling range to make the desired derivatives. In the refining of kerosene the starting material is called kerosene extract. In the refining of cracked gasoline or pressure distillate the material is known as pressure distillate extract.

Any hydrocarbon material may be treated with the polar solvents mentioned'above and the extract utilized to give the corresponding derivatives when treated according to the description submitted herein.

In the following example of the succeeding steps of my process, an extract obtained from kerosene by treatment with liquid sulphur dioxide was used.

The extract was first treated with sulphuric acid (93.19% ILS'OQ for the removal of impurities soluble in this medium, as for example unsaturated hydrocarbons. A combination of these with the acid settled to the bottom of the treating receptacle and was drawn olf. This acid sludge can be used for the recovery of alcohol and other valuable products, but for the purpose of this description it is an impurity. The hydrocarbon mixture left after the acid treatment is believed to be a mixture of aromatic, hydro-aromatic, and partially hydrogenated aromatic compounds. This hydrocarbon mixture was fraotionatedand a 100 c. c. portion boiling from 196 F. to 292 F., by the standard Engler method for gasoline, was nitrated for four hours with a mixture of 100 c. c. concentrated sulphuric acid and 1000. c. concentrated nitric acid. After the first half hour the temperature was held at 140 to 150 F. Reddish brown fumes were evolved during the treatment. At the end of four hours the mixture was poured on ice and a yellowish brown liquid separated at the bottom of the ice mixture. This, I believe, was the mono-nitro compound, it giving the characteristic odor and being heavier than water. This mono-nitro compound was separated and re-nitrated with 150 gms. of sulphuric acid and gms. of fuming nitric acid. After a couple of hours yellow needle-like crystals separated in the mixed acid mixture. The

" oil mixture was poured on ice and the yellow crystalline solid was recovered. This was recrystallized from alcohol and was found to have a melting point of 175 C. A mixed melting point determination with 2-5-di-nitro benzoic acid showed no lowering. The compound formed, therefore, was 2-5-di-nitro benzoic acid, the hydrocarbon either having been nitrated directly and a side chain oxidized to form the carboxyl group, or a hydro-aromatic compound was oxidized to form an aromatic hydrocarbon, which was in turn nitrated, and a side chain oxidized.

Another fraction obtained from kerosene extract boiling from 173 to 181 F. upon nitration as above, gave meta-dinitro benzene, which upon recrystallization from alcohol melted at 194 F. and showed no change in a mixed melting point with pure meta di-nitro benzene.

Another example of my process with an extract obtained from pressure distillate made by cracking California petroleum gave results similar to the above. Fromthis data it seems that I have both concentrated the true aromatic compounds, which are known to be present in small amounts in petroleum, in theextract,or have oxidized the hydro-aromatic compounds of various degrees of hydrogenation first, and then nitrated the resulting aromatic compound.

While this process has been done experimentally by means of nitration, I believe that other derivatives of aromatic compounds, such as the bromide, chloride, or the free aromatics themselves may be made by concentration, oxidation, and, or, conversion of the aromatic or hydro-aromatic hydrocarbons of petroleum in a relatively small volume of extract. At present these types of compounds are only obtained from coal tar and I believe that the manufacture of them through this process from petroleum constitutes a valuable step in advance.

I claim 1. The method of producing a nitro benzene derivative which comprises treating a hydrocarbon distillate containing unsaturated, hydroaromatic, and aromatic compounds with liquid sulphur dioxide to form an extract, separating from said extract the unsaturated hydrocarbon compounds, nitrating the remainder of said extract until the crystalline bodies separate out.

i 2. The method of producinganitro benzene derivative which comprises treating a hydrocarbon distillate containing unsaturated, hydroaromatic, and aromatic compounds with liquid sulphur dioxide to form an extract, separating from said extract the unsaturated hydrocarbon compounds, fractionating the remainder to give a cut of approximately 17 0180 F. and nitrating this out until the crystalline bodies separate out.

8. The method of producing metadinitrobenzene which comprises treating a liquid sulphur dioxide extract of a hydrocarbon distillate containing unsaturated, h'ydroaromatic, and aromatic compounds having a boiling point range ofapproximately 170180 F. with a nitrating agent, until the crystalline bodies separate out and recovering metadinitro-benzene.

4. The method of producing 2-5 dinitro benzoic acid, which comprises treating a hydrocarbon distillate containing unsaturated, hydroaromatic and aromatic compoun with liquid sulphur dioxide to form an extract, separating from said extract the unsaturated hydrocarbon compounds,'fractionating the remainder to give a cut of approximately 290 E, nitrating this out until the crystalline bodies separate out, and recovering 2-5 'dinitro benzoic acid. a

In testimony whereof I have signed my name to this specification.

HARRY K. IHRIGQ 

